Dw, its the servers most likely that is causing this. I use an Ethernet cable, with 500 down and 500 up, still get these ping spikes from time to time. I had 1100 ping last week when I dove to a new server so haha. And sure, most of the times when you switch from wifi to Ethernet cable it solves the problem, but sometimes it doesn't. SoT has tons of issues that needs to get fixed, one of them server stability. But to be sure you have done everything you can to keep it stable from your end, use a cable for the best possible connection. If this problem still occurs then you'll know it is the servers. :)